This graph is in the xy plane (I forgot to label it). I'm not really sure where to go from here, or if this is the right way to look at it. How do I get an equation representing the change in density of the disk?

Edit:

I'm still playing with this and I've set up the following idea:

I know that when r = 0, density = 15, and when r = 5, density= 0, which gives me two points (0,15) and (5,0). If I make these into a linear function, I get -3r. Is that anywhere close to right?

October 16th 2010, 04:44 PM

Ackbeet

No, I'd say you need to try again with your density function. The density-intercept of -3r is not the required 15. I think you have the right slope, though. If the density is f(r) = -3r + b, find b. Plug that into your integral.